Urban Transport energy efficiency and environmental sustainability continue to present big challenges for city leaders and policy think tanks. As the share of the world's population living in cities grows to nearly 70 per cent between now and 2050, urban transport energy consumption is forecast to double to meet the travel demand in the world's future cities.

A pioneering exploration of four cities where East meets West and past becomes future: St. Petersburg, Shanghai, Mumbai, and Dubai. Every month, five million people move from the past to the future. Pouring into developing-world "instant cities" like Dubai and Shenzhen, these urban newcomers confront a modern world cobbled together from fragments of a West they have never seen. Do these fantastical boomtowns, where blueprints spring to life overnight on virgin land, represent the dawning of a brave new world? Or is their vaunted newness a mirage?

For as long as humans have gathered in cities, those cities have had their shining—or shadowy—counterparts. Imaginary cities, potential cities, future cities, perfect cities. It is as if the city itself, its inescapable gritty reality and elbow-to-elbow nature, demands we call into being some alternative, yearned-for better place.